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用ＤＶ－Ｘα－ＳＣＣ方法和自然键轨道法研究了［Ｂｅ（ＮＭｅ２）２］３分子的电子结构和化学键．进而根据Ｎａｔｉｅｌｏ和Ｍｅｄｒａｎｏ键级定义计算了分子中有关原子间的键级，根据徐光宪共价新定义计算了其中铍原子的共价．结果表明，四配位的铍原子与邻近的４个Ｎ原子各形成了一个σ键，键级均为０．７２；三配位的铍原子除与两个桥联Ｎ原子各形成一个σ键（键级均为０．７７）外，还与端接Ｎ原子形成了两个共价键，键级为１．４６，其中一个为σ键，另一个为π键．按徐光宪共价新定义，铍原子共价均为６．由于铍原子间键级仅为０．０８，可以认为该分子中不存在金属－金属键
The electron structure and chemical bond of [Be (NMe2) 2] 3 have been studied by DV-Xα-SCC method and natural bond orbital method. Furthermore, according to the definitions of the bond-level of Natielo and Medrano, the bond-level between the atoms in the molecule was calculated. According to the new definition of covalentness by Xu Guangxian, the covalent bond of beryllium atom was calculated. The results show that the four-coordinated beryllium atoms form a σ bond with the adjacent four N atoms, and the bond order is 0.72. The three-coordinated beryllium atom forms a σ bond with each of the two bridging N atoms (0.77 for both bond levels), and formed two covalent bonds with the terminating N atom, with a bond level of 1.46, one of which is a sigma bond and the other a π bond. By Xu Guangxian new definition of covalent, beryllium atom covalent are 6. Since the bond between beryllium atoms is only 0.08, it can be assumed that there is no metal-metal bond in the molecule